This invention relates generally to ventilation systems and, more specifically, to an improved ventilation system for an absorption refrigerator located within a recreational vehicle.
It is common for recreational vehicles to have refrigerators on board for cooling and preserving food and drinks in a cooled compartment. These refrigerators are usually absorption-type refrigerators which use a heat source to effect refrigeration. An absorption refrigerator typically has a heat generator which heats a solution of a refrigerant and an absorbent. The heat releases the refrigerant from the absorbent to form a high pressure refrigerant vapor. The refrigerant vapor is condensed in a cooling condenser. Low pressure solution from the heat generator is sprayed on the refrigerant vapor in an absorber to absorb the vapor. The absorption causes the pressure of the vapor to be reduced, thereby causing evaporation in an evaporator between the condenser and the absorber. The refrigerant vapor expands in the evaporator which causes a temperature drop in the refrigerant which is used to cool the compartment. The solution of refrigerant and absorbent is then pumped back to the heat generator where it is again heated.
Absorption refrigerators are favored in vehicles, such as campers or recreational vehicles, because a compressor is not required and the heat generator can be an electrical resistance heater or a gas heater. The electrical resistance heater can be powered by a direct current supply of the vehicle or a commercial alternating current supply such as those available at campgrounds. The gas heater can be fueled by propane gas which is usually carried on recreational vehicles.
It is typically necessary to cool the condenser and absorber of the refrigerator. This is economically achieved by creating a "natural draft" airflow over the condenser and absorber. To create this airflow, a generally vertical duct is provided to permit airflow over the condenser and absorber. In some installations, a fan is provided to create a "forced draft" airflow either continuously or only when conditions are unsuitable for natural draft airflow.
Typically the rear wall of the refrigerator is substantially parallel with and faces an outer wall of the recreational vehicle so that the duct is located between the rear wall of the refrigerator and the outer wall of the recreational vehicle. Locating a refrigerator against an outer wall, however, limits the arrangement of objects within the recreational vehicle, such as cabinets, partitions, furniture, and other appliances.
In response to this limitation, the refrigerator and air passage have been located inwardly from all exterior walls by extending the inlet duct through the floor and the outlet duct through the roof. See, for example, U.S. Pat. No. 5,355,693, the disclosure of which is expressly incorporated herein in its entirety by reference. As a result, the refrigerator can be oriented in any manner relative to the outside walls when adequately spaced from the outside walls. When the rear wall of the refrigerator is perpendicular to and near an outside wall, however, chassis structure of the vehicle may not permit an adequate inlet vent through the floor. Accordingly, there is a need in the art for an improved ventilation system which permits an absorption-type refrigerator to be placed with its rear wall perpendicular to and near an outside wall of the recreational vehicle.